Private On-Site Wastewater - Saraniecki Flashcards
What is Biological Oxygen Demand?
BOD
the difference between initial dissolved O2 and a later period of time O2 sample
usually 5 days BOD5
What is Chemical oxygen demand?
COD
a measure of the amount of O2 consumed chemically by oxidation of organic and inorganic materials in water
Define domestic sewage
used water from a home or community - includes bath, toilet, laundry, kitchen
What is black water?
from WC, lavatory, privy
What is grey water?
all other domestic wastewater - shower, laundyr, bath - considered pathogenic
define point source pollution
any discernible, confined, or discrete conveyance from which pollutants may be discharged
pipe, ditch, well, vessel, vehicle
define nonpoint pollution
not a point source
is manmade/man-induced resulting in the alteration of the chemical, physical, biological, or radiological integrity of water
What is combined sewer?
storm water and domestic sewage combined in same pipe
What is a separate sewer system?
storm water and domestic sewage are collected separately
What are suspended solids?
solids that are visible and in suspension in water
What does the inlet baffle of a septic tank do?
directs the flow
minimizes turbulence
minimizes short circuiting
What does the outlet baffle of a septic tank do?
assures outflow comes from clear zone
holds floating scum in tank
What is the inlet and outlet baffle elevation differential?
3 inches
What do effluent screens do?
designed to keep larger suspended solids in the tank
control outflow rate
protect downstream components from larger suspended solids
replace outlet baffle typically
require riser to grade for access to screen for inspection, cleaning, replacement
What is the ultimate purpose of a septic tank?
24-72 hour watertight detention tank
conditions sewage to be more readily percolated into subsoil
What are the three main functions of a septic tank?
removal of solids
biological treatment
sludge and scum storage
What anaerobic digestion occurs and where does this occur in a septic system?
operates in anoxic environment
treats sewage
very slow process
happens in septic tank
Describe aerobic digestion and where does it occur?
treats sewage
rapid treatment proces
produces lowest suspended solid effluent
ex: aerobic treatment plant
What is generally considered in the system design of a septic system?
(5)
flow
waste strength
soil permeability - perc tests and soils investigations
limiting layer - high water table, bedrock
site geography - slope, lot size, etc
What is typical waste strength for residential aka domestic waste?
BOD5 and TSS ~200-300 ppm
ammonia ~60ppm
Describe a general percolation test method
6 steps
- dig 1x1 hole 24-30” deep
drop 2” gravel at bottom of hole
saturate hole 4 hours, let swell overnight
slowly pour 12” water
measure rate water drops every minute for fast soils
test is complete when 3 rate measurements at 6”-5” level become relatively equal
What unit do you calculate perc rate in?
minutes per inch
needs at least 3 tests for average
What is infiltration defined as?
movement of water into soil
What is percolation defined as
movement of water within soil matrix
What does perc rate control?
infiltration rate
What are the four soil sizes and types?
gavel - >2mm grain
sand 2mm>0.05
silt 0.25mm>0.002
clay less than 0.002mm
What is loam soil?
contains sand, silt, and clay in many different proportions
What type of soil typically drains well?
Sandy soil with some gravel
What type of soil typically doesn’t drain well?
clay loam and clay
What can you assume for soils that are yellow, brown, or red?
air and water pass through
What can you assume for soils that are blue or grey?
saturated for a long time
What can you assumed for mottled brown or red soil?
fluctuating seasonal high water table
poor aeration
unsuitable for septic system
What can you assume for greyish soil?
iffy
generally unsuitable
What is the limiting layer?
seasonal high water table
fractured limestone layer - dolomite
dense soils with little permeability
gravelly soils with fast permeablility
fragipan layers that restrict water flow and root penetration
What does design flow determine?
tank capacity
What does waste strength determine?
method of pretreatment - septic tank, sand filter ATP
What do design flow in conjuction with application rate determine?
square footage of seepage area
What sludge maintenance can be performed?
tank inspected annually
tank cleaned every 3 years or sooner
ATP if necessary
What are some causes of septic system failure?
poor design
hydraulic overload - seasonal high water (tank floats), excessive water use, leaky plumbing
system abuse - flushing non-digestables or chemicals
system damage - baffles, soil compaction
improper connections
uneven settlement of system parts - piping, d box, tank
What is ideal one-site wastewater treatment?
primary sedimentation
secondary treatment - flocculation with O2
tertiary treatment to remove nitrogen and phosphorous
chlorination
dechlorination
What are common sewage-borne bacteria?
(7_
shigella
salmonella
campylobacter enteritis
cholera
yersinia
E coli
Enterohemorrhagic E coli (EHEC)
Shigella (sonnei and flexneri)
Sx?
Common?
Inoculum?
Reserv?
Trans?
bacillary dysentery - bloody stool
450k us cases, 72% sonnei
small inoculum 10-200 colony forming unit
res: only humans
trans: fecal/oral, contaminated food and water, anal sexual contact, flies via mechanical
Salmonelly typhi
aka?
common?
transmission?
similar to?
aka typhoid fever
NOT salmonellosis
400 cases, 21 min worldwide 200-600k fatal
trans: contaminated food or water - shellfish from sewage water, raw fruits and veg fertilized by nightsoil, flies
similar to paratyphoid fever which is milder
Salmonellosis
agent?
reservoir?
trans?
implications?
agent: Salmonella typhimurium and eteritidis - diarrhea
res: wild and domestic animals, poultry swine turtles iguanas cats and dogs
trans: fecally contaminated water, p2p if diarrhea is presernt
implications: mass feeding and sanitation problems
Campylobacter jejuni
aka?
reservoir?
transmission?
Can trigger?
Gastroenteritis - travelers diarrhea
most common us diarrhea bacteria
res: wild and domestic animals - cattle chicken puppies kittens
Campylobacter jejuni
aka?
reservoir?
transmission?
Can trigger?
Gastroenteritis - travelers diarrhea
most common us diarrhea bacteria
res: wild and domestic animals - cattle chicken puppies kittens
trans: undercooked chicken, pork, raw milk, fecally contaminated food and water, p2p rare
can trigger Guillain-Barre syndrome
E coli O157:H7
aka?
sx?
res?
trans?
shiga toxin producing e. coli
often grossly bloody diarrhea
can lead to HUS and kidney failure
res: ruminant animals - cattle, goats, sheep, elk, infected humans
trans: raw or undercooked ground beef, sprouts, raw milk and juice, lettuce, dry salami, REI, petting zoos, raw human and cattle sewage
E. coli - non special
enterotoxigenic
res: humans, pigs, sheep, goats, cattle, dogs, horses
trans: contaminated food and water
aka travelers diarrhea
Where is EPEC found?
enteropathogenic E coli
disease of infants via contaminated fake mothers milk thanks to contaminated water
What is EIEC?
res is only humans
transmission from contaminated foor
What is EAEC?
res only humans
infant diarrhea 3rd in world cause
Vibrio cholera
common?
reservoir?
trans?
implications?
0-5 cases per year
res: mostly humans
trans: ingestion of food or water infected with the feces or vomit of infected humans, or raw or undercooked contaminated shellfish
implications: risk of ourbreak
What are the common sewage-borne viruses? (5)
adenovirus
poliovirus
norwalk virus
HAV
HRV
Hepatitis A
reservoir?
trans?
common?
res: humans and other primates
trans: fecal/oral, p2p, contaminated food and water
uncommon, vaccines available
HRV
transmission?
Rotavirus
fecal/oral - nosocomial disease, contaminated food and water, contact with contaminated fomites
most common child severe diarrhea cause, 55k kids hospitalized each year
Human Adenovirus
sx general?
res?
trans?
significance?
HAdv are the cause of a wide spectrum of acute and chronic diseases
reservoir: humans
trans: p2p, indirect contact via fomites, poorly maintained swimming pools
it is so common that it is about to become the new indicator for sewage contamination
Poliovirus
sx?
agent?
reservoir?
trans?
viral infection presenting with acute onsite flaccid paralysis
Poliovirus genus Enterovirus
res: humans
trans: p2p fecal/oral, water and food rarely implicated
What are the common sewage-borne helminthes?
ascariasis
ancylostomiasis
taeniasis
dracunculiasis
trichuriasis
Ascaris lumbricoides
reservoir?
transmission?
large intestinal roundwork, few to no sx
res: humans, ascarid eggs in soil
trans: ingestion of eggs from soil or uncooked produce
Ancylostomiasis
aka?
transmission?
sx?
prevention?
hookworm disease
most common roundworm of humans
eggs passed in human stools and hatch in the soil
larvae penetrate the skin then migrate to blood, heart, lungs
causes anemia and protein deficiency
prevention - sanitary sewage disposal and shoes
Taeniasis
agents? (2)
reservoir?
transmission?
prevention?
Taenia saginata - cattle
Taenia solium - swine
reservoir: humans, cattle and pigs intermediate hosts
transmission: larval cysts from raw or undercooked infected meat, contaminated food or water
prev: keep cattle and swine away from human waste
Dracunculus medinensis
aka??
where?
Res?
transmission?
control?
Guinea-worm infection, occurs in dry regions Africa and Asia
res: only humans
trans: ingestion of larvae from stagnant fresh water
infective dose: one cyst egg or larvae
control: filtration
Trichuriasis
aka?
reservoir?
transmission?
roundworm
800mil worldwide
res: humans, mostly poor warm areas
trans: consumption of eggs that have previously passed thru the colon - raw veggies or dirt
What are the four protozoa found in sewage?
Giardia lamblia
Taenia saginata and solium
Entamoeba histolytica
Balantidium coli
Amoebiasis
agent?
reservoir?
trans?
Entamoeba histolytica - travellers diarrheares: humans
trans: cysts - contaminated food and water, oral/anal
cysts are cl resistant
Balantidiasis
agent?
sx?
reservoir?
transmission?
Balatidium coli
protozoan infection of the color - diarrhea, dysentery
reservoir: swine and rates
trans: ingestion of cysts from feces of infected hosts
Spirochete bacterial disease
aka?
caused by?
trans?
res?
Leptospira spp
Weil’s disease
spirochete bacteria
zoonosis of domestic and wild animals - skin or mucosal contact with infected water contaminated with urine
res: rats, swine, cattle, dogs, raccoons
Methemoglobinemia
cause?
Blue baby syndrome
bacterial conversion of nitrate to nitrite
consumed by kids by contaminated well from ag runoff or powdered fake mothers milk and concentrated juices rehydrated with contaminated water
treat with 1% methylene blue
What are biosolids?
undigested solids that must be periodically removed by licensed state haulers to either sewage treatment plant or landfill
ocean dumping banned since 1991
How can raw sewage be treated in an emergency?
Lime:
estimated gallons = LxWxAvgdepthx7.5
20-25 lbs/1000gallons
slaked or ag lime acceptable, not pellets
confirm by testing pH - 12 or higher 30 min minimum
Approved uses for reclaimed water?
irrigation (not veggie or herb garden without bubbler system)
street sweeping
power generation
fountains
fire protection
dust control
aquifer recharge
What are the 4 manure pit dangers?
hydrogen sulfide
methane
carbon dioxide
ammonia
